(1) Field of the Invention
The present invention relates to a method for preparing an epoxy compound in a high yield by oxidizing an olefin compound having 4 to 16 carbon atoms with an organic hydroperoxide.
(2) Description of the Prior Art
Epoxy compounds are very reactive and important compounds which can be converted into polyethers, glycols and other kinds of chemicals by reactions with various compounds.
Heretofore, these epoxy compounds have been manufactured by forming a corresponding halohydrin from an olefin compound having a corresponding carbon skeleton, and then subjecting the halohydrin to a dehydrogenation reaction by the use of a basic compound such as calcium hydroxide. Further, as another method of oxidation, an epoxidation technique is also known which utilizes an organic peracid such as performic acid, peracetic acid or perbenzoic acid.
Still another method for manufacturing epoxy compounds has been extensively researched which comprises the epoxidation reaction of an olefin compound where an organic hydroperoxide is used as the oxidizing agent. In this epoxidation reaction, a catalyst is used which is an organic metallic compound of a metal selected from the group consisting of molybdenum, tungsten and vanadium.
In order to improve the selectivity of the desired epoxidation reaction, various methods are known in which a second substance is used together with a conventional known epoxidation catalyst in the epoxidation reaction of the olefin with the organic hydroperoxide. For example, J. Catal., 43, 380-383 (1976) describes that, in oxidizing 1-octene with cumene hydroperoxide in the presence of a molybdenum naphthenate catalyst to form 1-octene oxide, an oxide of an alkaline earth metal such as barium oxide, strontium oxide, calcium oxide or magnesium oxide is used simultaneously so as to remarkably heighten the selectivity of the epoxidation. Further, Japanese Patent Laid-open No. 133279/1981 discloses a method for epoxidizing an olefin compound having 4 carbon atoms with an organic hydroperoxide in which the reaction occurs in the presence of an organic amine compound and an organic metallic compound of a metal selected from the group consisting of molybdenum, vanadium and tungsten.
The halohydrin method which is a typical example of the above-mentioned conventional technique, has the disadvantages that the halogen for example, chlorine, consumed by the halohydrin is completely converted into its less valuable inorganic salt, i.e., calcium chloride, and a dilute aqueous solution containing this inorganic salt is byproduced in large quantities. Therefore, for the purpose of finding oxidizing methods in which no halogen is used, research has been made into an oxidizing method using an organic peracid and into a catalytic epoxidation method using an organic hydroperoxide as the oxidizing agent.
However, in an epoxidation reaction with an organic peracid, the ring-opening-addition reaction of the produced epoxide with a byproduced acid cannot be avoided, with the result that the epoxy compound cannot be obtained in a high yield.
Further, for example, in the aforesaid catalytic reaction of using an organic hydroperoxide, an olefin compound can be epoxidized in the presence of an organic compound of molybdenum as the catalyst, but there is the problem that the selectivity is not always high. Accordingly, there is a need to establish a method for preparing an epoxy compound with a high selectivity.